gnu: tryton.scm: Reorder packages.

gnu: tryton.scm: Reorder packages.

Move proteus near the top, as it is a package to be used by other
ications.  Sort all "tryton modules" (python-trytond-*) alphabetically.

* gnu/packages/tryton.scm (python-proteus): Move behind tryton.
  (python-trytond-account, python-trytond-account-invoice,
  python-trytond-account-invoice-stock, python-trytond-account-product,
  python-trytond-analytic-account, python-trytond-company,
  python-trytond-country, python-trytond-currency, python-trytond-party,
  python-trytond-product, python-trytond-purchase,
  python-trytond-purchase-request, python-trytond-stock,
  python-trytond-stock-lot, python-trytond-stock-supply): Sort alphabetically.